In order to physically and electrically connect a light bulb to another article, such as a lamp, appliance or other article, one end of the light bulb typically includes a "lamp cap" connected to the bulb which includes exterior threads about its periphery. The lamp or appliance includes a threaded socket for complementary threaded engagement with the lamp cap and electrical contacts for providing electricity to the light bulb and illuminating the bulb when desired. An example of such a socket is illustrated in U.S. Pat. No. 5,176,532 which is assigned to the assignee of the present invention.
In order to ensure that a new or replacement bulb will fit a desired socket, thread standards have been developed for the bulb and socket. The threads utilized are relatively large and few in number to enable ease of assembly and manufacture.
Upon installing bulbs within sockets, however, care must be taken to ensure that the bulb is properly threaded and seated within the socket so that electrical contact is established. The large and few threads specified by the standard, however, promote cross-threading where the bulb appears properly secured within the socket but electrical contact is not properly established.
This can be a particular problem in the manufacture and assembly of appliances, such as refrigerators, freezers and similar household devices which require a light bulb. Such light bulbs are typically manually threaded into sockets secured to the appliance which is moving along an assembly line. Due to the speed of the assembly line, cross-threading of light bulbs can be a problem and is typically not discovered until later in the inspection process requiring further assembly time to remove and properly reinstall the bulb within the socket.
It therefore would be desirable to provide a socket for receiving a bulb therein which is designed to prevent cross-threading of the bulb and socket regardless of the orientation of the bulb and its threads.